1. Field of the Invention
The present invention relates to a pulse combustion device adapted to a liquid vessel to heat an amount of liquid such as cooking oil or other fluid medium stored therein, and more particularly to an improvement of a combustion chamber and a tailpipe arrangement in the pulse combustion device.
2. Description of the Prior Art
As shown in FIG. 4, a conventional pulse combustion device of this kind includes a cylindrical combustion chamber 1 having a forward end wall formed with an inlet port 2 and a rearward end wall formed with an exhaust port for connection to a tailpipe 3. In FIG. 5 there is illustrated a combustion chamber 5 of another conventional pulse combustion device which is in the form of a volute casing having a forward end wall formed with an inlet port 6 in a tangential direction and a side wall formed with an exhaust port for connection to a tailpipe 7. In such pulse combustion devices, the combustion chamber 1 or 5 is immersed in liquid in a vessel associated thereto, and a spark plug 4 is mounted on the forward end wall of the combustion chamber at a position adjacent the inlet port.
The cylindrical combustion chamber 1 of FIG. 4 can be manufactured at a low cost by welding the component parts thereof. On start up, however, the mixture of gaseous fuel and air from inlet port 2 may not be rapidly ignited by energization of the spark plug 4. When resonant combustion of the mixture is initiated, a periodic reverse flow of the combustion products from tailpipe 3 causes a turbulent flow of the incoming mixture in the combustion chamber 1 as shown by dotted arrows in FIG. 4, resulting in irregular combustion of the mixture. This causes unstable combustion of the mixture and results in an increase of harmful components such as CO, HC and the like in the combustion products exhausted from tailpipe 3. On the other hand, the volute combution chamber 5 of FIG. 5 causes therein a vortex flow of the incoming mixture from inlet port 6. Thus, on start up, the mixture is rapidly ignited by energization of the spark plug 4 without any delay of time, and the vortex flow of the incoming mixture may not be disturbed by a periodic reverse flow of the combustion products from tailpipe 7. The volute combustion chamber 5, however, must be made of heat-resistant cast-iron, resulting in an increase of manufacturing cost.